Tacrolimus EP Impurity B

Chemical Name: (3S,4R,5S,8R,9E,12S,14S,15R,16S,18R,19S,26aS)-8-ethyl-5,19-dihydroxy-3-[(1E)-1-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]prop-1-en-2-yl]-14,16-dimethoxy-4,10,12,18-tetramethyl-3,4,5,6,8,11,12,13,14,15,16,17,18,19,24,25,26,26a- octadecahydro-7H-15,19-epoxypyrido[2,1-c][1,4]oxaazacyclotricosine-1,7,20,21(23H)-tetrone (as per EP)